A Global Navigation Satellite System (GNSS) is a satellite system that is used to pinpoint the geographic location of a GNSS receiver. Spoofing of a GNSS system is typically used to cause erroneous navigation data to be output from a navigation system in a vehicle that is using the GNSS satellite system. FIG. 2A shows an exemplary GNSS spoofing attack on an unprotected vehicle 51. As shown in FIG. 2A, the spoofing system includes an antenna 306 that inputs satellite signals via wireless data links 321, 322, and 323 from the plurality of respective satellites 351, 352, and 353 that are in view of the vehicle 51. The satellite signals received at the antenna 306 are modified by the spoofer-electronics-and-logic 305. The spoofing system also includes antenna 307 that emits a modified satellite signals via wireless data link 315 to the navigation system on the vehicle 51. The modified satellite signals received via data link 315 at the GNSS receiver of the unprotected vehicle 51 is stronger in amplitude than the true, unmodified satellite signals received at GNSS receiver 110 via wireless data link 311, 312, and 313 from the respective antennas 351, 352, and 353. In this manner, the spoofer-electronics-and-logic 305 provides false data to the vehicle 51 so the navigation system in the vehicle 51 indicates the vehicle 51 is at a location that is different from the actual location of the vehicle 51.
The aviation industry and the marine industry desire anti-spoofing capability to protect high-value assets (e.g., aircraft and water-based vehicles) from a spoofing attack. Currently available techniques to detect a spoofing attack require multiple antennas on the vehicle that may also be articulated and move. This is not a desirable solution since it adds significant cost to a GNSS installation.
Some of the currently available anti-spoofing techniques identify outlier GNSS data, which is excluded from the data used to generate a navigation solution. The outlier data can be a vestigial signal from a code or carrier Doppler shift frequency.
In other currently available techniques, inertial sensors provide acceleration measurements for a GNSS enabled device. A location of the GNSS enabled device is approximated based on a known location and the acceleration measurements. The approximate location is compared with the received positioning data to determine whether the received positioning data is within a confidence interval of the prediction.